A comprehensive consideration of bias voltage and temperature to extract the intrinsic frequency response of photodiodes

Abstract

Frequency response is one of the most important characteristics of photodiode (PD). The upper limitation of the bandwidth of a PD is determined by its intrinsic frequency response. Based on the extraction method to extract the intrinsic frequency response, we take a further study to analyze the impact of the reverse bias voltage and the temperature on the frequency response of PDs. With the help of physical model, the experimental data and fitted results based on the reverse bias voltage and temperature separately are discussed, then the most reliable intrinsic frequency response of a PD is obtained. photodiode, intrinsic frequency response, extraction method, optoelectronic Citation: Chen S F, Li L, Wu H, et al. A comprehensive consideration of bias voltage and temperature to extract the intrinsic frequency response of photodiodes. The trend in optical communication systems towards higher transmission rates has led to the development of widebandwidth optical receivers. The bandwidth of a PD is determined by the response of extrinsic parasitic network and the intrinsic frequency response of the diode [1]. The mostly used fabricated PD actually contains package parasitic network, chip parasitic network and intrinsic photodiode [2,3]. The intrinsic frequency response offers the upper limitation of the bandwidth of a PD, since the effect of all the parasitic network can be eliminated by elaborate design.To get the intrinsic frequency response of a PD, the response of cascaded network including a modulator, a photodiode and test fixtures is measured by vector network analyzer (VNA) in the conventional calibration method, and then the effect of the modulator and test fixtures is removed [4][5][6]. However, this method is much complicated, and the effect of parasitic parameter becomes obvious when the working frequency is increased. A simple method to extract the intrinsic frequency response was proposed based on the principle that the scattering parameters of parasitic network usually do not change with the bias voltage of photodiode [7]. However, the working temperature of a PD varies in practice use and has impact on the response characteristics, so the temperature factor should be taken into account when extracting the intrinsic frequency response.Just as the bias voltage, the temperature does not affect the scattering parameters of the parasitic network, thus we take a further study on the extraction method considering both temperature and bias voltage factors. In this paper, the theory of the extraction method is briefly described, and then the impact of temperature and bias voltage on the drift velocity of carriers in the photodiode is analyzed. By subtracting and curve fitting the experimental data based on bias voltage and temperature separately, the results are obtained and discussed upon the definition of parameters and physical meaning. The best result is selected after the comparison, thus the intrinsic frequency response of PD and the physical parameters are finally obtained.